Futaba Attack-Sport FP-T2NCR
I received a 27 MHz transmitter as part of an eBay buy that had sadly been left with the batteries in and, probably, turned on (we've all done it). I was very reluctant to let it go to waste, so I went on the hunt for options to repair it and I thought this might be a useful guide to others.
The terminals were coated in residue from the batteries and the corrosion of the terminals themselves. NB From this point forward please wear appropriate PPE, gloves, goggles, etc. And protect surfaces and other precious things.
I followed an Instructables guide using Tesco's own distilled vinegar and cotton wool buds to neutralise as much of the acid as I could. I found a dab in the vinegar and the press and hold, taking care to control runs, technique worked best. NB the wire entry holes allows a path for the vinegar to the PCB. I carefully wiped the residue away and collected it in a container for disposal with the used buds.
At this stage it was becoming clear that they needed more than just neutralisation. I didn't want to risk damaging the rest of the handset, so I opted for removal of the terminals themselves. I cut the red and black wires (NB Take a photo of position prior to removal) and then carefully extracted each terminal from the handset by pricing with a sharp screwdriver from the bottom edge of the battery terminal. With the terminals removed, I cleaned the rest of the battery compartment with the vinegar and removed all traces of corrosion product. Tip: Remove any traces of vinegar afterwards with a wet wipe or similar damp cloth. I cleaned the rest of the transmitter with moistened cotton buds and wet wipes.
I followed another guide from Instructables and using a 50:50 mixture of lemon juice and bicarbonate of soda (also Tesco's own) I cleaned what remained of the battery terminals removing all corrosion. Tip: Cocktail sticks are good for gently scraping off the corrosion product. It was at this stage I realised that the battery contacts were in a very, very bad condition. My first try was a search for replacements, which proved unsuccessful, so I tried Futaba's agent in the UK who informed with that he parts were no longer available/obsolete. I looked through various catalogues from the usual electronics suppliers but couldn't find the right size and shape because the battery compartment is very compact.
Plan B: What I was able to find was Traxxas Part 2226, which are a coiled wire design rather than plate type design. As I was out of options, I ordered some from Modelsport. Please be aware the guide from here is now an unofficial mod.
The coiled wire design is a good fit for the width of the terminals and fits well in the locating grooves. However, they do sit a little low in the compartment. I had some packers, the type for PVC window fitting, so I trimmed down a 0.5 mm thickness piece into 2 x 8 mm strips and slid these down into the channel before sliding the wire contacts in on top. Using a soldering iron, I removed what was left of the old wire connections. I purchased 22 AWG and 24 AWG wire from component-shop (eBay seller). and remade the wires from the battery terminals back to the main switch with a little extra length (20 cm). I personally went for 22 AWG cable. Looking at the original cable 24 AWG would probably have been fine.
Once the transmitter was reassembled, I fitted new batteries and a new aerial (available from digitalfocus on eBay). Once together everything fits quite nicely in place and, most importantly, it powered on. NB It may be necessary to secure the coiled wire terminals with a little bit of superglue or similar.